Acquisition, restructuring and management fee costs - Summary of total acquisition, restructuring and management fee costs (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 26, 2021	Sep. 27, 2020	Mar. 29, 2020	Sep. 26, 2021		Sep. 27, 2020
Business Combination and Asset Acquisition [Abstract]
Acquisitions	[1]	$ 204	$ 137		$ 3,415		$ 1,301
Restructuring	[2]	140	955	$ 4,323	1,265
Management fees	[3]	23,274	894	2,665	25,813
Earn out adjustment					17,173	[4]
Total acquisition, restructuring and management fees		$ 23,618	$ 1,986	$ 8,289	$ 47,666

[1] Includes professional fees for legal, accounting, consulting, administrative, and other professional services directly attributable to potential acquisitions.

[2] Includes costs incurred as part of the restructuring of operations including professional and consulting services.

[3] Includes acquisition costs and management fees paid to Sentinel Capital Partners, including a fee of $23,275 paid in the 13-week period ended September 26, 2021 upon the Closing of the Business Combination

[4] A fair value adjustment to the contingent consideration payable from the Simpson acquisition